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Experimental environment D sJ ’s and their properties X(3872)... ...and also Y(3940) cc recoil spectrum pentaquarks? Conclusion. New Resonances at Belle. B. Golob University of Ljubljana, Slovenia Belle Collaboration.

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slide1

Experimental environment

  • DsJ’s and their properties
  • X(3872)...
  • ...and also Y(3940)
  • cc recoil spectrum
  • pentaquarks?
  • Conclusion

New Resonances at Belle

B. Golob

University of Ljubljana, Slovenia

Belle Collaboration

B. Golob, Belle Cracow Epiphany Conference, 2005

slide2

Experimental environment

Mt. Tsukuba

e-

KEKB

B

Belle

Υ(4s)

~1 km in diameter

> 900 pb-1/day (~1 M BB/day)

e+

Integrated luminosity

∫Ldt = 255 fb-1 on reson.

30 fb-1 off reson.

~280 M BB

B

Oct ‘04

May ‘99

KEKB asymmetric B

factory

Υ(4s)

B. Golob, Belle Cracow Epiphany Conference, 2005

slide3

Experimental environment

Central Drift

Chamber

e+

3.5 GeV

s(pt)/pt=

0.3% √pt2+1

3(4) layer

Si vtx det.

e-

8 GeV

combined particle ID

e(K±)~85%

e(p±→K±)<~10%

@ p<3.5 GeV/c

Aerogel

Cherenkov

Counter

(n=1.015-

1.030)

m and KL

identification

(14/15 lyrs

RPC+Fe)

1.5T SC

solenoid

EM Calorimeter

CsI (16X0)

B. Golob, Belle Cracow Epiphany Conference, 2005

slide4

B

ECM/2

signal

ECM/2

U(4s)

e-

e+

signal

B

B

∑ pi, ∑ Ei

continuum

Experimental environment

Off reson. data:

continuum only

On reson. data:

BB (spherical) separated

from continuum

(jet shaped) on basis of

topological variables

e.g. angle

between B

direction

and beam

axis

B. Golob, Belle Cracow Epiphany Conference, 2005

slide5

DsJ states

Production in continuum

DsJ+(2460)→Ds+g

DsJ+(2317)→Ds+p0

DsJ+(2460)→Ds*+p0

3.4

3.0

Mass (GeV)

2.6

Ds*+

2.2

Ds+

1.8

86.9 fb-1,PRL92,012002(2004)

M(DsJ(2317))=2317.2±0.5±0.9 MeV

M(DsJ(2460))=2456.5±1.3±1.3 MeV

Masses lower than

predicted

in potential models;

Widths consistent

with zero

B. Golob, Belle Cracow Epiphany Conference, 2005

slide6

DsJ states

Production in

B decays

Helicity angle:

Ds

DsJ

B

D

q

DsJ+(2317)→

Ds+p0

g,p0

J=1

DsJ+(2460)→

Ds*+p0

DsJ+(2460)→

Ds+g

J=1

J=2

J=0

275M BB,BELLE-CONF-0461

DsJ+(2317)→Ds+p0

DsJ+(2460)→Ds+g

B(0,±) → D(±,0)DsJ

Data agree with JP=0+ (DsJ(2317)) and 1+ (DsJ(2460))

Br(B→D-DsJ+(2317))=(10.3±2.2±3.1)x10-4

B. Golob, Belle Cracow Epiphany Conference, 2005

slide7

DsJ states

First observation of B0→DsJ+K-

M(Dsp0)-M(Ds)

DE

6.8 s signif.

0.2 0.3 0.4 0.5 0.6 (GeV)

-0.10 0 0.10 (GeV)

c

s

b

d

u

K+

Br(B0→DsJ(2317)+K-)∙Br(DsJ(2317)+→Ds+p0)

W

s

Br(B0→Ds+K-)

B0

d

152M BB,hep-ex/0409026

Br(B→D-DsJ+(2317))∙Br(DsJ(2317)+→Ds+p0)

DsJ

Br(B→D-Ds+)

d

DsJ(2317)→Dsp0

(Ds→fp,K*K,KSK)

Br(B0→DsJ(2317)+K-)∙ Br(DsJ(2317)+→Ds+p0)=

(5.3 ± 1.4± 0.7 ± 1.4)x10-5

4-quark

content?

<2.5x10-5 @90% CL

<0.94x10-5

<0.40x10-5

B→DsJ(2317)p-

B→DsJ(2460)K+

B→DsJ(2460)p-

= 0.13 ± 0.05

= 1.8 ± 0.6

B. Golob, Belle Cracow Epiphany Conference, 2005

slide8

Observed by Belle with

152M BB

B± → K± p+p-J/y

l+l-

How about with 275M BB?

152M BB,

PRL91,262001

(2003)

275M BB,S.Olsen,GHP’04

X(3872)

Calculate Mbc in 5 MeV bins ofM(p+p-J/y)

M(p+p-l+l-)-M(l+l-)

3865

MeV

48.6±7.8 evts.

M=3872.4±0.7 MeV

3870

MeV

no. of

B’s in

bins of

M(p+p-J/y)

3875

MeV

M(p+p-l+l-)

B. Golob, Belle Cracow Epiphany Conference, 2005

slide9

B± → K± p+p- p0 J/y

Mbc andDE

in 25 MeV

bins of

M(p+p-p0)

X(3872)

-0.1 0.1

5.20 5.25 5.30

Mbc

DE

M(p+p-p0J/y)= M(X)± 3s

no. of B’s in

bins ofM(p+p-p0)

13.1±4.2 evts.

consistent with 0

First observation of decay mode

other than p+p-J/y;

subtreshold decay to wJ/y

(DD* molecule)

C(X(3872))=+1

B. Golob, Belle Cracow Epiphany Conference, 2005

slide10

Dalitz plot for

B→ KwJ/y

Y(3940)

B→ Kp+p- p0 J/y

B± → K* J/y; K*→ K± w

Events in DE, Mbc signal region

resonant

structure?

M2(J/yw)

M(p+p-p0J/y)

B→

KwJ/y

M(p+p-p0)

M2(Kw)

For these

B→ KwJ/y

plot Mbc, DE in bins

ofM(wJ/y)

B. Golob, Belle Cracow Epiphany Conference, 2005

slide11

B± → K± wJ/y

No. of B’s

in bins of

M(wJ/y)

275M BB,

hep-ex/0408126

Y(3940)

40 MeV binsM(wJ/y)

3897

MeV

3937

MeV

3977

MeV

large

deviations

from phase

space

M(Y)=3943±11±8 MeV

G=87±22±13 MeV

58 ± 11 evts.

Fit with

added

BW

Relatively large signal at

lowM(wJ/y)

Br(B→YK)Br(Y→wJ/y)=

(7.1±1.3±3.1)x10-5

B. Golob, Belle Cracow Epiphany Conference, 2005

slide12

cc recoil spectrum

X

e-

e+

J/y

hc

cc0

hc(2s)

well established method(e.g. double cc

production)

Reconstruct

J/y →l+l-

Calculate recoil mass (mass of X):

285 fb-1,T.Ziegler,GHP’04

new resonance

N=148 ± 33 (4.5 s)

M=3940 ± 11 MeV

Reconstruction of

additional D or D*

besideJ/y→

- new resonance decays

to DD*;

- not seen in J/y w

probably not Y(3490)

confirmation of hc(2s) after 1st

observation by Belle

B. Golob, Belle Cracow Epiphany Conference, 2005

slide13

Pentaquark searches

M(pK-)

y[cm]

L(1520)

M(pKS)

x[cm]

(KN+(1540)X)

(KN(1520)X)

< 2%(90%CL)

155M BB,hep-ex/0411005

Searches in decays,“high energy” (charm baryon,B)

Searches in secondary inter.,“low energy”

select pK secondary vtx

detector “tomography”:

M(pK-)fit

with D-wave

BW and

treshold

funct.;

L parameters

in agreement

with PDG

M(pKS) fit with 3rd order

poly.and narrow sig.(2 MeV)

at different m

assuming Br(+→pKS)=25%

B. Golob, Belle Cracow Epiphany Conference, 2005

slide14

KEKB is also a great source of cc states

  • Some expected, mainly unexpected/puzzling

observations/discoveries

D**broad states

PRD69,112002

Y(3940)

hep-ex/0408126

DsJ properties

BELLE-CONF-0461

hep-ex/0409026

hc(2s)

PRL89,102001

PRD70,071102

PQ

searches

hep-ex/0411005

X(3872)→ wJ/y

S.Olsen,GHP’04

Sc(2800)

hep-ex/0412069

resonance in cc

recoil

T.Ziegler,GHP’04

Lc+ p structure

hep-ex/0409005

Conclusions

range of questions:

understanding

all properties

as expected?

why such

properties?

what are they?

will be addressed as more statisticsis collected

B. Golob, Belle Cracow Epiphany Conference, 2005

slide16

Pentaquark searches

backup slide

Searches in decays,“high energy”

charm baryon decays, B decays

Searches in secondary inter.,“low energy”

S(1670)+

Xc+

Q(1540)+

131 fb-1

Lc+ → p Ks Ks

M(pKSKS)

M(pKS)

charm

baryon

decays

Lc+ → pK+ K-

Q*(1600)++

M(pK+)

M(pK+K-)

B. Golob, Belle Cracow Epiphany Conference, 2005

slide17

Pentaquark searches

B0  p pKS

B0  p+ D(*)-p

B+  p pK+

B0 pD0p

B0  p+D-p

155M BB,hep-ex/0411005

backup slide

B decays

Qc0

Q(1540)+

Qc*+

Q*(1600)++

303

±21

evts.

M(Qc0)=3099 MeV(H1)

s=3.5 MeV (det. resol.)

@90% CL

B. Golob, Belle Cracow Epiphany Conference, 2005

slide18

Pentaquark searches

L(1520)

p

p

formation

p(pK-)~500 MeV

K-

K-

L(1520)

p

p

production

majority

K-

K-

assuming Br(+→pKS)=25%

Br((1520)→pK-)=

0.5 Br((1520)X→NK)

ratio of e from MC

(KN+(1540)X)

(KN(1520)X)

< 2%(90%CL)

backup slide

L(1520)

spectrum

(fit to

M(pK-) in

mom. bins

formation

p

non-zero

strangeness

most pK vtx

produced by

strange

particles

vtx with addit.

track

distance

pK vtx –

next track

distance

pK vtx –

next K±

cm

B. Golob, Belle Cracow Epiphany Conference, 2005

slide19

Production in B decays

DsJ states

backup slide

B(0,±)→ D*(0,±)DsJ

DsJ+(2317)→

Ds+p0

DsJ+(2460)→

Ds*+p0

DsJ+(2460)→

Ds+g

DE side band

M(DsJ) side band

All events in Mbc signal region

B. Golob, Belle Cracow Epiphany Conference, 2005

slide20

Production in B decays

DsJ states

backup slide

Decay channel Br signif.

B  D DsJ(2317) [Dsp0] 10.1  1.5  3.0 9.5s

B  D DsJ(2317) [Ds*g] 4.0-1.4+1.5 (<8.4) 3.5s

B  D DsJ(2460) [Ds*p0] 14.8-2.5+2.8  4.4 8.6s

B  D DsJ(2460) [Dsg] 6.4  0.8  1.9 11s

B  D DsJ(2460) [Ds*g] 2.6-1.0+1.1 (<5.7) 3.0s

B  D DsJ(2460) [Dsp+p-] 1.0-0.4+0.5 (<2.3) 2.6s

B  D DsJ(2460) [Dsp0] 0.2-0.5+0.7 (<1.7) --

B  D* DsJ(2317) [Dsp0] 3.1-1.7+2.1 (<8.5) 2.0s

B  D* DsJ(2460) [Ds*p0] 28.7-6.4+7.4  8.6 6.9s

B  D* DsJ(2460) [Dsg] 12.7-2.0+2.2  3.8 10s

Br(DsJ(2460)→Ds+g)/Br(DsJ(2460)→Ds*+p0)=0.43±0.08±0.04

Br’s from DE fits in Mbc and M(DsJ) signal region

Largest syst. uncertainty from p0 eff. and D branching

fractions

B. Golob, Belle Cracow Epiphany Conference, 2005

slide21

DsJ states

First observation of B0→DsJ+K-

backup slide

W exchange

DsJ(2317) K-

16.6±4.4 evts.

DsJ(2317) p+

FSI

DsJ(2460) K-

tree,4 quark

content

DsJ(2460) p+

B. Golob, Belle Cracow Epiphany Conference, 2005

slide22

Potential model prediction

for cu:

D** states

65M BB,PRD69,112002

backup slide

B+→D-p+p+

~1100

evts.

D side band

B+→D*-p+p+

D0*, D1’ broad states

D1, D2* narrow states

~550

evts.

Modes used:

D0→K-p+, K-p+p+p-

D+→K-p+p+

D*+→ D0p+

Dalitz plot analysis

B. Golob, Belle Cracow Epiphany Conference, 2005

slide23

D** states

B+→

D-p+p+

B+→

D*-p+p+

backup slide

M(Dp)min

M(Dp)max

D0*

proj. of

4D fit

D1’

proj. of

2D fit

D2*

D1

D2*

Dv*,Bv*

M(Dp)min

M(Dp)min

DE side band

bckg. subtracted

B. Golob, Belle Cracow Epiphany Conference, 2005

slide24

D** states

backup slide

M(D0*)= 2308±17±15±28 MeV;

G(D0*)= 276±21±18±60 MeV;

M(D2*)= 2461.6±2.1±0.5±3.3 MeV;

G(D2*)=45.6±4.4±6.5±1.6 MeV;

larger than WA

(23±5 MeV),

but no interf.

effects

taken into account;

Focus exp.

30.5±4.2 MeV

errors: stat.

syst.

model

varying selection;

track, PID eff.;

hep-ex/0011044

= 0 for default fit

= 240-360 if no D0* or

JP=1-,2+

fits with

Dv*,Bv*,constant

Br(B- → D0*p-)Br(D0*→D+p-)=(6.1±0.6±0.9±1.6)x10-4

B. Golob, Belle Cracow Epiphany Conference, 2005

slide25

D** states

backup slide

M(D1’)= 2427±26±20±15 MeV;

G(D1’)= 384±90±24±70 MeV;

M(D1)= 2421.4±1.5±0.4±0.8 MeV;

G(D1)=23.7±2.7±0.2±0.4 MeV;

in agreement

with WA

= 0 for default fit

= 100-170 if no D1’ or

JP=1-,2+

Br(B- → D1’p-)Br(D1’→D*+p-)=(5.0±0.4±1.0±0.4)x10-4

narrow reson. (D1,D2*) comprise 36±6% of Dpp final state

63±6% of D*pp final state

QCD sum rule: narrow reson. dominate D(*)pp state

LEP: B→D(*)pln also not dominated by narrow reson.

B. Golob, Belle Cracow Epiphany Conference, 2005

slide26

X(3872)

p+

p-

M too low; G too small

K

B

X

angular dist’n rules out 1+-

q

J/y

M too low; G(gJ/y) too small

G(gcc1) too small; mpp wrong

pp hc should dominate ppJ/y

G( gcc2 & DD) too small;

mpp wrong

backup slide

Angular distrib. for

21P1 (hc’) top+p-J/y

hc”

hc’

cc1’

y2

hc2

y3

expected

forhc’

X

|cosq|

c2/nof=75/9

B. Golob, Belle Cracow Epiphany Conference, 2005

slide27

B± → K± p+p-p0 J/y

X(3872)

signal

v

iii

iv

ii

i

Side regions

B± → K±wJ/y

wband

M(p+p-p0J/y)

Xband

fit Mbc

and DE

M(p+p-p0)

DEin

25 MeV

bins of

M(p+p-p0)

Possible contr.K±wJ/y0.75 ± 0.14

B. Golob, Belle Cracow Epiphany Conference, 2005

slide28

B± → K± p+p-p0 J/y

X(3872)

backup slide

B± → K1(1270)J/y

4.3±6.2

region I

M(X)-M(3p) signal region

region III

6.4±5.6

Simultaneous fit to DE and Mbc

distrib. for M(p+p-p0)>750 MeV

non-resonant, peaking bckg.

1.3±1.0 (scaled to sig. area)

signific.:

main syst. uncertainty:

contrib. of peaking bckg.

and K±wJ/y: -20%;

M(3p)>750 MeV: +25%

6.4s (5.0s if 2 events

peaking backg.)

B. Golob, Belle Cracow Epiphany Conference, 2005

slide29

Nw=74±14

Y(3940)

backup slide

B→ KwJ/y

M(p+p-p0)

DE, Mbc signal region

20% variation

included in

syst. error.

Ks,K± yields

consistent

with acc.

ratio.

acceptance

KS

M(wJ/y)

M(wJ/y)<3997 MeV

(first 3 bins in

M(wJ/y));

no resonance

in Kw in this

M(wJ/y) region

M(Kw)

DE, Mbc side band:

Nw=14±10(non-w 3p)

fraction of true w

in signal: 0.90±0.18

(in syst. error)

B. Golob, Belle Cracow Epiphany Conference, 2005

slide30

cc recoil spectrum

X

e-

e+

J/y

backup slide

Calculate recoil mass

(mass of X):

Reconstruct

J/y →l+l-

calibrate withe+e-→(2S) 

(2S) → J/y p+p-

<1% bckg.

Shift of Mrec againts J/y

with same momentum bias found

Mrec(J/) < 3 MeV/c

for Mrec(J/)  3 GeV/c

fitted with MC

with free Mrec2

off-set

M2rec=0.0100.009 GeV2/c4(data/MC);

introduce momentum scale bias in

MC to reproduce M2rec

B. Golob, Belle Cracow Epiphany Conference, 2005

slide31

cc recoil spectrum

D(*)

?

D(*)

N=9.93.3

(4.5s)

Y

e-

e+

J/y

N=4.12.2

(2.1s)

backup slide

Reconstruct

J/y →l+l-; D0→K-p+,D+→K-p+p+

Use events with

Mrec(J/y D)≈M(D*)

Calculate Mrec(J/y)

(mass of resonance decaying

toDD(*))

B. Golob, Belle Cracow Epiphany Conference, 2005

slide32

Isotriplet of charmed baryons

M(pK-p+)

275M BB,hep-ex/0412069

Lcp+ final state; Lc → pK-p+

Lcp0

Lcp-

Lcp+

+p

2.8x103

evts.

2.2x103

evts.

1.5x103

evts.

M(Lcp)-M(Lc)

Lc++(2880)→

Lc+p+p-

Sc(2800)0 M-M(Lc)= 515.4 ± 3.2+2.1-6.0 MeV

Sc(2800)+M-M(Lc)= 505.4 +5.8–4.6+12.4-2.0 MeV

Sc(2800)++M-M(Lc)= 514.5 ± 3.3+2.8-4.9 MeV

G~61-75 MeV

xp

Peterson fragm.

function

s(e+e-→Sc(2800)X)Br(Sc(2800)→Lcp)

= 2-2.6 pb (± 1-2 pb)

0.2 0.4 0.6 0.8 1.0

B. Golob, Belle Cracow Epiphany Conference, 2005

slide33

Lc+ p structure

Sc(2455)0

Sc(2520)0

B-→ Lc+ p p-

D(1600)

D(2420)

3-body baryon production in

B decays: baryon-antibaryon

system peaked near treshold

Fits to DE

in mass bins

264±20 evts.

Lc+ →pK-p+,pKS,Lp+,

pKSp+p-,Lp+p+p-

L→ pp-

BW peak + feed

down fromB-→ Lc+ D

M = 3.35 ± 0.02 GeV

50 ± 10 evts.(5.6 s)

G~70 MeV

B. Golob, Belle Cracow Epiphany Conference, 2005

slide34

Lc+ p

Lc+ p structure

Br(B-→ Sc(2455)0 p)=(3.67+0.74-0.66 ± 0.36 ± 0.95)∙10-5

Br(B-→ (Lc+ p)p-)=(3.87+0.77-0.72 ± 0.43 ± 1.01)∙10-5

Sc(2455)0 p

Sc(2455)0 p

backup slide

simultaneous fit

to 6 DE distrib.;

Ni=SjeijYj

Lc+ D(2420)

Lc+ D(1600)

Lc+ D(1232)

due toBr( Lc+ → pK-p+ )

M=3.35 +0.01-0.02 ± 0.02 GeV

G=0.07 +0.04-0.03± 0.04 GeV

from different bckg. param.

B. Golob, Belle Cracow Epiphany Conference, 2005

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